Phthalate metabolites in loggerhead marine turtles (Caretta caretta) from the Mediterranean Sea (East Spain region)

The exposure of marine reptiles to phthalates has received considerable attention due to the ubiquitous occurrence of these contaminants in the marine environment. The occurrence of phthalate metabolites is established in human populations and marine mammals, but data is scarce for marine reptiles. In this study, concentrations of 18 phthalate metabolites were determined in liver samples from 79 loggerhead marine turtle (Caretta caretta) samples collected between 2016 and 2021 in the limits of the Valencian Community (East Spain). For this purpose, the phthalate metabolites were purified from the livers by solid phase extraction and were quantified by UPLC-MS/MS. Fifteen phthalate metabolites were detected in the samples. Monoethyl phthalate (mEP), monomethyl phthalate (mMP), mono-n-butyl phthalate (mBP), phthalic acid (PA) and mono-n-hexyl phthalate (mHxP) were the most abundant metabolites, accounting for detection rates >85%. The highest median concentrations were found for PA (24.2 ng/g dry weight, d.w.) and mHxP (20.3 ng/g d.w.) followed by mMP (12.0 ng/g d.w.), mEP (5.76 ng/g d.w.) and mBP (4.26 ng/g d.w.). The sum of the medians of these five phthalate metabolites (Σ5PhMet) indicated that concentrations were higher for turtles during year 2020, while a negative association was found between [Σ5PhMet] and the turtle size. To our knowledge, this is the first study on the biomonitoring of 18 phthalate metabolites in loggerhead marine turtles, and results show that western Mediterranean loggerhead turtles are usually exposed to these contaminants.